The slew of goals only brought added comfort for Celtic. The team needed a lift following last Tuesday night's defeat by Juventus in the Champions League, and Dundee United obliged. The clinical nature of the home side's play, and the relentless ambition, brought six goals but also a reminder that the players need not feel abashed. This side is, still, significantly better than the rest of the Scottish Premier League.
"It was a fantastic performance," Neil Lennon, the Celtic manager, said. "The players wanted to put in a strong performance, they were hurting, but they picked themselves up very well. I've got a good team here and I want them to keep showing that."
The mood of the Celtic supporters might still have been a little raw, but sympathy was not part of United's repertoire. The away fans chanted "Juve, Juve" but that was only mildly upsetting for the hosts compared to the initial efforts of the team. Only 10 minutes had passed when Gary Mackay-Steven stole the ball from Charlie Mulgrew and hared towards the Celtic penalty area before releasing a pass to Stuart Armstrong.
Showing admirable composure, the young midfielder strode into the box and slid a precise shot beyond Fraser Forster, the Celtic goalkeeper, and into the net.
The goal ought to have been mortifying to Celtic, since the immediate obligation was to raise the spirits of their supporters. Efe Ambrose had been singled out as the culprit of that defeat, but he received a warm welcome, and responded with the equaliser. His header came from cross by Kris Commons, who had so pointedly criticised Ambrose's defending in the immediate aftermath of the Juventus game.
The pair were prominent throughout. Ambrose veered between assurance and alarm on his forays forward with the ball from centre-back. Commons was more conventionally involved, though, and there was crispness to his technique, as well as resourcefulness, when he chested down Emilio Izaguirre's cross and volleyed a shot on target while he fell backwards. The ball struck Cierzniak's foot before spinning into the goal off the underside of the crossbar.
United were not immediately suppressed, with Mackay-Steven in particular proving too quick and elusive for Adam Matthews. The Celtic right-back's mind must have been addled, since he tugged back Johnny Russell – before executing a perfect sliding tackle – inside the penalty area. Bobby Madden, the referee, saw the initial infringement and awarded a spot-kick, but Forster was equal to Jon Daly's firmly-struck effort.
The reprieve was a fillip for Celtic, because the game was still evenly balanced. Minds were focused, though, and the home side began to attack with slick intent. One smart passing move ended with Joe Ledley firing the ball into the United net, via a deflection off Sean Dillon, the United defender. The visitors, then, must have recognised that fortune was stacked against them.
Further confirmation came early in the second half, when Anthony Stokes was bundled over by Barry Douglas as he chased Gary Hooper's through ball.
On this occasion, Commons was decisive from the penalty spot and Celtic could begin to consider this a restorative occasion.
Stokes considered it a personal opportunity, since he added the fifth – lashing a 20-yard shot beyond Cierzniak – and the sixth – from close-range when James Forrest's header was saved – after a long spell when his career at the club appeared to be over. Russell's late consolation was only a footnote to a game that Celtic dominated.
"I'm disappointed with the goals that we lost," Jackie McNamara, the United manager, said. "They were soft. A couple of the players were too accepting [of the defeat], which I'm not happy about."
Celtic (4-1-2-1-2): Forster; Matthews, Ambrose (Kayal, 70), Wilson, Izaguirre; Mulgrew; Wanyama (Forrest, 76), Ledley; Commons (Rogic, 73); Hooper, Stokes.
Dundee Utd (4-2-3-1): Cierzniak; Watson, Dillon, McLean, Douglas; Flood (Ryan, 38), Rankin; Russell, Armstrong, Mackay-Steven; Daly (Gardyne, 78).
Referee Bobby Madden.
Man of the match Kris Commons.